Start by asking about a new idea, "How would I prove this idea false?" This is the key to scientific thinking -- scientists first ask themselves, "What would falsify this idea?"
When you acquire an idea, you're borrowing someone else's thought. But to simultaneously learn how to think and make an idea your own, before taking the idea seriously, assume it's false and test it for validity, using your personal knowledge base.
Here's a classic example -- a friend says, "All swans are white." To make this idea yours, don't confirm it by locating ten more white swans. Instead, try to find a black swan. Even if you fail, your personal version of the idea will be, "It appears that most swans are white."
As it happens, this skeptical outlook is the key to the so-called "Enlightenment," an historical change that dethroned blind acceptance of ideas. This paradigm was best expressed in the Royal Society's (https://royalsociety.org/about-us/who-we-are/history/) motto "Nullius in verba" or "Take no one's word for it." Written in 1660, this motto expresses the essence of scientific, skeptical thinking, just as true today -- indeed, more true now than ever.
Being doubtful and skeptical of received ideas, scientifically testing new ideas, makes you intellectually stronger, and strengthens the surviving ideas as well.
With proper training, your immune system can protect you from germs. In the same way, with proper training, your brain can protect you from bogus ideas. Train your brain.